The compound 1-(3-chloroallyl)-3,5,7-triaza-1-azonia-adamantane chloride (CTAC) is a well established biocidal agent that is particularly effective in aqueous dispersions and emulsions. It is known, however, that when CTAC is used in clear or light-colored aqueous formulations, the formulation visibly yellows on aging. This is an undesirable phenomenon, especially for the cosmetics, paints, and coatings industries.
CTAC can be blended with other biocidal compounds to increase its efficacy. For instance, blends of CTAC and 1,2-benzisothiazolin-3-one (BIT) have been observed to provide a synergistic effect under certain concentration ratios. That is, the combined materials result in improved biocidal properties than would otherwise be expected based on their individual performance at the particular use-concentration. The observed synergy permits reduced amounts of the materials to be used to achieve acceptable biocidal properties. Biocidal formulations of CTAC with a second biocide, such as BIT, are therefore highly desirable.
Difficulties can arise, however, in formulating CTAC with a second biocide into a stable blend, particularly where the two agents have differing physical and/or chemical compatibilities. This is the case, for instance, with CTAC and BIT. Such formulations tend to phase separate. Blend stability, however, is an important attribute of such formulations as it impacts the handling and storage of the materials as well as inventory and transportation costs.
The tendency of CTAC to discolor upon aging and the difficulty of formulating CTAC with other biocides into color and phase stable blends are significant limitations of currently known systems.